The catalytic and electrocatalytic behavior of the La0.6Sr0.4Co0.8Fe0.2O3 (LSCF) perovskite deposited on yttria-stabilized zirconia (YSZ) was studied during the reaction of methane oxidation. Experiments were carried out in a well-mixed (CSTR) reactor at atmospheric pressure, in the 600-900 degrees C range. When, instead of co-feeding with methane in the gas phase, oxygen was electrochemically supplied as O2-, considerable changes in the methane conversion and product selectivity were observed. Catalytic and electrocatalytic results were compared to those obtained when the LSCF served as a dense mixed-conducting membrane supplying oxygen to the methane feed stream because of the oxygen partial-pressure gradient across the membrane.